Liquid crystal display screen

ABSTRACT

A liquid crystal display screen includes an upper board, a lower board opposite to the upper board, and a liquid crystal layer located between the upper board and the lower board. The upper board includes a touch panel. The touch panel includes a plurality of transparent electrodes. At least one of the transparent electrodes includes a carbon nanotube structure.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No.12/459,545, filed Jul. 2, 2009, entitled, “TOUCH PANEL, LIQUIDCRYSTAL DISPLAY SCREEN USING THE SAME, AND METHODS FOR MAKING THE TOUCHPANEL AND THE LIQUID CRYSTAL DISPLAY SCREEN”, which application arefully incorporated by reference herein. This application is related toapplications entitled, “TOUCH PANEL”, filed on Aug. 13, 2009, andapplication Ser. No. 12/583,162; “METHOD FOR MAKING TOUCH PANEL”, filedon Sep. 3, 2009, and application Ser. No. 12/584,415; “METHOD FOR MAKINGLIQUID CRYSTAL DISPLAY ADOPTING TOUCH PANEL”, filed on Aug. 13, 2009,and application Ser. No. 12/583,160; “METHOD FOR MAKING LIQUID CRYSTALDISPLAY ADOPTING TOUCH PANEL”, filed on Sep. 03, 2009, and applicationSer. No. 12/584,410; “LIQUID CRYSTAL DISPLAY”, filed on Jul. 02, 2009,and application Ser. No. 12/459,566; and “LIQUID CRYSTAL DISPLAY”, filedon Aug. 13, 2009, and application Ser. No. 12/583,161.

BACKGROUND

1. Technical Field

The present disclosure relates to a liquid crystal display screen.

2. Description of Related Art

Liquid crystal display screens are relatively thin, light weight, havelow power consumption. Liquid crystal display screens have been widelyused in various electronic apparatuses having displaying functions suchas computers and televisions as well as on portable devices such asmobile phones, car navigation systems, and personal digital assistants(PDAs).

Following the advancement in recent years of various electronicapparatuses, toward high performance and diversification, there has beencontinuous growth in the number of electronic apparatuses equipped withoptically transparent touch panels in front of their respective liquidcrystal display screens. A user of any such electronic apparatusoperates it by pressing or touching the touch panel with a finger, apen, a stylus, or another like tool while visually observing the displayof the liquid crystal display screen through the touch panel. Therefore,a demand exists for touch panels and liquid crystal display screensusing the same that provide superior in visibility and reliableoperation.

Up to the present time, different types of touch panels, includingresistance, capacitance, infrared, and surface sound-wave types havebeen developed. Due to their higher accuracy and low-cost of production,the resistance-type touch panels have been widely used.

Typical resistance-type touch panel includes an upper substrate and alower substrate. The upper substrate includes an optically transparentupper conductive layer and two upper electrodes connected to theoptically transparent upper conductive layer at two edges along the Xdirection respectively. The lower substrate includes an opticallytransparent lower conductive layer and two lower electrodes connected tothe optically transparent upper conductive layer at two edges along theY direction respectively. The upper substrate is a transparent andflexible film or plate. The lower substrate is a transparent and rigidplate made of glass. The optically transparent upper conductive layerand the optically transparent lower conductive layer are formed ofconductive indium tin oxide (ITO). The upper electrodes and the lowerelectrodes are formed by silver paste layers.

In operation, an upper surface of the upper substrate is pressed with afinger, a pen or the like tool, and visual observation of a screen onthe display device provided on a back side of the touch panel isallowed. This causes the upper substrate to be deformed, and the upperconductive layer thus comes in contact with the lower conductive layerat the position where pressing occurs. Voltages are applied successivelyfrom an electronic circuit to the optically transparent upper conductivelayer and the optically transparent lower conductive layer. Thus, thedeformed position can be detected by the electronic circuit.

However, the ITO layer generally has poor mechanical durability, lowchemical endurance, and provides for uneven resistance over an entirearea of the touch panel. Moreover, the ITO layer has relatively lowtransparency in a humid environment. All the above-mentioned problems ofthe ITO layer tend to yield a touch panel with somewhat low sensitivity,accuracy, and brightness. Furthermore, the ITO layer is generally formedby means of ion-beam sputtering, and this method is relativelycomplicated.

What is needed, therefore, is to provide a liquid crystal display screenusing a touch panel having good durability, high sensitivity, accuracy,and brightness to overcome the aforementioned shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present touch panel, the liquid crystal displayscreen using the same, and the methods for making the touch panel andthe liquid crystal display screen can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, the emphasis instead being placed upon clearlyillustrating the principles of the present touch panel, the liquidcrystal display screen using the same, and the method for making thetouch panel and the liquid crystal display screen.

FIG. 1 is a schematic top view of a first electrode board of a touchpanel in accordance with the embodiment of FIG. 3.

FIG. 2 is a schematic top view of a second electrode board of the touchpanelin accordance with the embodiment of FIG. 3.

FIG. 3 is a cross-sectional view of the touch panel in accordance withan embodiment.

FIG. 4 is a circuit diagram of the touch panel of FIG. 3.

FIG. 5 shows a Scanning Electron Microscope (SEM) image of a carbonnanotube film.

FIG. 6 is a structural schematic of a carbon nanotube segment in thecarbon nanotube film of FIG. 5.

FIG. 7 shows a Scanning Electron Microscope (SEM) image of a carbonnanotube composite structure.

FIG. 8 is a diagram showing a relationship between resistances anddistance between two locations on the carbon nanotube compositestructure of FIG. 7.

FIG. 9 is a cross sectional view of a liquid crystal display deviceusing the touch panel in FIG. 3.

FIG. 10 is a top view of a thin film transistor panel in the liquidcrystal display screen of FIG. 9.

FIG. 11 is a cross sectional view of a thin film transistor in the thinfilm transistor panel of FIG. 10.

FIG. 12 shows a Scanning Electron Microscope (SEM) image of a carbonnanotube film used in the thin film transistor of FIG. 11.

FIG. 13 is a schematic view of the lightening of the liquid crystaldisplay screen of FIG. 9 during use.

FIG. 14 is a schematic view of the liquid crystal display screen of FIG.9 during use.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate at least one embodiment of the present touch panel, theliquid crystal display screen using the same, and the method for makingthe touch panel and the liquid crystal display screen in at least oneform, and such exemplifications are not to be construed as limiting thescope of the invention in any manner.

DETAILED DESCRIPTION

Reference will now be made to the drawings to describe, in detail,embodiments of the present touch panel, the liquid crystal displayscreen using the same, and the method for making the touch panel and theliquid crystal display screen.

Referring to FIGS. 1 to 3, a resistance-type touch panel 10 in oneembodiment includes a first electrode plate 12, a second electrode plate14 facing to the first electrode plate 12, and a plurality of dotspacers 16 disposed between the first electrode plate 12 and the secondelectrode plate 14.

The first electrode plate 12 includes a first substrate 120, a pluralityof first transparent electrodes 122, and a plurality of first signalwires 124. The plurality of first transparent electrodes 122 are locatedon the first substrate 120, and aligned along a first direction. Theplurality of first transparent electrodes 122 are parallel to each otherand uniformly spaced. In this embodiment, the first direction is alongthe X axis. Each of the plurality of the first transparent electrodes122 has a first end 122 a and a second end 122 b. The first end 122 a ofeach of the plurality of the first transparent electrodes 122 isconnected to an X-coordinate drive power source 180 through one of theplurality of the first signal wires 124. The X-coordinate drive powersource 180 applies a drive voltage to the plurality of first transparentelectrodes 122. The second end 122 b of each of the plurality of thefirst transparent electrodes 122 is connected to a sensor 182 throughone of the plurality of the first signal wires 124. A distance betweeneach two parallel and adjacent first transparent electrodes 122 can bein the range from about 20 microns to about 50 microns.

The second electrode plate 14 includes a second substrate 140, aplurality of second transparent electrodes 142, and a plurality ofsecond signal wires 144. The plurality of second transparent electrodes142 are located on the second substrate 140, and aligned along a seconddirection. The second transparent electrodes 142 are parallel to eachother and uniformly spaced. In this embodiment, the second direction isalong the Y axis, and the second direction is perpendicular to the firstdirection. Each of the plurality of the second transparent electrodes142 has a first end 142 a and a second end 142 b. The first end 142 a ofeach of the plurality of the first transparent electrodes 142 isconnected to a Y-coordinate drive power source 184 through one of theplurality of the second signal wires 144. The Y-coordinate drive powersource 184 applies a drive voltage to the plurality of secondtransparent electrodes 142. The second end 142 b of each of theplurality of the second transparent electrodes 142 is grounded. Thedistance between each two parallel and adjacent second transparentelectrodes 142 can be in the range from about 20 microns to about 50microns.

Referring to FIG. 4, the first transparent electrodes 122 each arestrip-shaped films or wires and are disposed on the first substrate 120at regular intervals and spaced from each other. The number andconfiguration of the first transparent electrodes 122 can be varried.The number of the first transparent electrodes 122 generally depends onthe desired sensitivity as well as the desired transparency. A sparsearrangement of the electrodes can increase the transparency, butdecrease the sensitivity of the touch panel 10. More films generallyincrease sensitivity, but may reduce transparency (and vice versa). Withregards to configuration, the first transparent electrodes 122 and 142generally map the touch panel 10 into a coordinate system such as aCartesian coordinate system, a Polar coordinate system or some othercoordinate system. When a Cartesian coordinate system is used, the firsttransparent electrodes 122 typically correspond to X coordinates and thesecond transparent electrodes 142 typically correspond to Y coordinates.When a Polar coordinate system is used, the first transparent electrodes122 typically correspond to radial (r) and the second transparentelectrodes 142 typically correspond to angular coordinate (θ). In theshown embodiment, the first transparent electrodes 122 are arrangedalong the X coordinate corresponding to the Cartesian coordinate.

The second transparent electrodes 142 each are also strip-shaped filmsor wires and are disposed on the second substrate 140. The secondtransparent electrodes 142 are arranged along the Y coordinatecorresponding to the Cartesian coordinate and orthogonal to the firsttransparent electrodes 122.

The first substrate 120 can be a transparent and flexible film or platemade of polymer, resin, or any other suitable flexible material. Thesecond substrate 140 can be a rigid and transparent board made of glass,diamond, quartz, plastic or any other suitable material, or can be atransparent flexible film or plate similar to the first substrate 120when the touch panel 10 is flexible. A material of the flexible film orplate can be selected from a group consisting of polycarbonate (PC),polymethyl methacrylate acrylic (PMMA), polyethylene terephthalate(PET), polyether polysulfones (PES), polyvinyl polychloride (PVC),benzocyclobutenes (BCB), polyesters, and acrylic resins. The thicknessof the first substrate 120 and the second substrate 140 can be in therange from about 1 millimeter to about 1 centimeter. In one embodiment,the first substrate 120 and the second substrate 140 are both made ofPET, and their thicknesses are both about 2 millimeters. It is to beunderstood that the material of the first substrate 120 and the secondsubstrate 140 should not be restricted to the above-mentioned materials,but can be any of various other materials that can provide a suitabletransparency and strength of the first substrate 120 and the secondsubstrate 140.

The first signal wires 124 and second signal wires 144 can be formed ofmaterials having relatively low resistance, such as ITO, antimony tinoxide (ATO), conductive resin, or any other suitable conductivematerials. When the material of the first and second signal wires 124,144 are to be shown, the diameter of the first and second signal wires124, 144 should be very small (e.g., less than 100 microns) to avoidlowering the transparency of the touch panel 10. More specifically, thefirst and second signal wires 124, 144 made of metal, ITO, or ATO can beformed by depositing, etching, or printing. In one embodiment, the firstand second signal wires 124, 144 are a plurality of carbon nanotubewires. A diameter of each of the carbon nanotube wires is in theapproximate range from 0.5 nanometers to 100 microns. The carbonnanotube wires include a plurality of carbon nanotubes joined end toend. It is noted that because the carbon nanotubes have a high specificsurface area, the carbon nanotube wires are adherent in nature. As such,the carbon nanotube wires can be directly laid on and adhered to thesubstrates. After adhered on the substrate, the carbon nanotube wirescan be treated with a solvent to increase the adhesion with thesubstrate.

In one embodiment, the first transparent electrodes 122 and the secondtransparent electrodes 142 include a carbon nanotube structure. Thecarbon nanotube structure can be in strip shaped or wire shaped. In thisembodiment, all the carbon nanotube structures are strip shaped. Thewidth of the carbon nanotube structures can be in the range from about20 microns to about 250 microns. A thickness of the carbon nanotubestructures can be in the range from about 0.5 nanometers to about 100microns. Here, each carbon nanotube structure has the width of 50microns, and the thickness of 50 nanometers.

The carbon nanotube structure can be composed of one single carbonnanotube film or include a plurality of carbon nanotube films stacked onand/or adjacent to each other. Thus, a thickness, length and width ofthe carbon nanotube structure can be set as desired and in a range wherethe carbon nanotube structure has an acceptable transparency.

The carbon nanotube film is formed by a plurality of carbon nanotubes,ordered or otherwise, and has a uniform thickness. The carbon nanotubefilm can be an ordered film or a disordered film. The ordered carbonnanotube film is consisted of ordered carbon nanotubes. The disorderedcarbon nanotube film is consisted of disordered carbon nanotubes.Ordered carbon nanotube films include films where the carbon nanotubesare arranged along a primary direction. Examples include films whereinthe carbon nanotubes are arranged approximately along a same directionor have two or more sections within each of which the carbon nanotubesare arranged approximately along a same direction (different sectionscan have different directions). Disordered carbon nanotube films includerandomly aligned carbon nanotubes. When the disordered carbon nanotubefilm comprises of a film wherein the number of the carbon nanotubesaligned in every direction is substantially equal, the disordered carbonnanotube film can be isotropic. The disordered carbon nanotubes can beentangled with each other and/or are substantially parallel to a surfaceof the disordered carbon nanotube film. In the ordered carbon nanotubefilm, the carbon nanotubes can be primarily oriented along a samedirection. However, the ordered carbon nanotube film can also havesections of carbon nanotubes aligned in a common direction. The orderedcarbon nanotube film can have two or more sections, and the sections canhave different alignments.

Length and width of the carbon nanotube film can be arbitrarily set asdesired. A thickness of the carbon nanotube film is in a range fromabout 0.5 nanometers to about 100 micrometers. The carbon nanotubes inthe carbon nanotube film can be selected from the group consisting ofsingle-walled, double-walled, multi-walled carbon nanotubes, andcombinations thereof. Diameters of the single-walled carbon nanotubes,the double-walled carbon nanotubes, and the multi-walled carbonnanotubes can, respectively, be in the approximate range from 0.5 to 50nanometers, 1 to 50 nanometers, and 1.5 to 50 nanometers.

The ordered carbon nanotube film can be formed by drawing a film from acarbon nanotube array. The ordered carbon nanotube film that drawn fromthe carbon nanotube array is a free-standing carbon nanotube film.Referring to FIG. 5 and FIG. 6, the drawn carbon nanotube film includesa plurality of successive and oriented carbon nanotubes 145 joined endto end by van der Waals attractive force. The carbon nanotubes 145 inthe drawn carbon nanotube film are substantially oriented along a samedirection. Specifically, the drawn carbon nanotube film includes aplurality of successively oriented carbon nanotube segments 143 joinedend-to-end by van der Waals attractive force therebetween. Each carbonnanotube segment 143 includes a plurality of carbon nanotubes 145parallel to each other, and combined by van der Waals attractive forcetherebetween. The carbon nanotubes 145 in each carbon nanotube segment143 are also oriented along a preferred orientation. A thickness of thedrawn carbon nanotube film ranges from about 0.5 nanometers to about 100microns. A maximum width and length of the drawn carbon nanotube filmdepends on the size of the carbon nanotube array from which it is drawn.In one embodiment, the width of the drawn carbon nanotube film can rangefrom 0.5 nanometers to 10 centimeters. The drawn carbon nanotube film isflexible and has a relatively high toughness due to the van der Wallsattractive force between the carbon nanotubes 145. The carbon nanotubes145 in the drawn carbon nanotube film are uniformly arranged andparallel to a surface of the drawn carbon nanotube film, and thus, thedrawn carbon nanotube film has excellent resistance distribution andlight transparence.

When the carbon nanotube structure includes at least two stacked drawncarbon nanotube films, an angle α between the preferred orientation ofthe carbon nanotubes in the two adjacent drawn carbon nanotube films isin the rang from above 0° to about 90°.

In one embodiment, the carbon nanotubes in the first transparentelectrodes 122 are arranged along the first direction, the carbonnanotubes in the second transparent electrodes 142 are arranged alongthe second direction. Thus, the conductivities of the first transparentelectrodes 122 and the second transparent electrodes 142 can be improvedby the aligned carbon nanotubes. As shown in FIG. 5, the majority of thecarbon nanotubes are arranged along a primary direction; however, theorientation of some of the carbon nanotubes may vary.

The drawn carbon nanotube film is formed by a drawing (or pulling)method. The method for fabricating the drawn carbon nanotube filmincludes the steps of: (a) providing a carbon nanotube array capable ofhaving a film drawn therefrom; and (b) pulling out a drawn carbonnanotube film from the carbon nanotube array, by using a tool (e.g.,adhesive tape, pliers, tweezers, or another tool allowing multiplecarbon nanotubes to be gripped and pulled simultaneously).

In step (b), the drawn carbon nanotube film can be formed by thesubsteps of: (b1) selecting one or more carbon nanotubes 145 having apredetermined width from the carbon nanotube array; and (b2) pulling thedrawn carbon nanotubes to form carbon nanotube segments 143 at aneven/uniform speed to achieve a uniform drawn carbon nanotube film.

In step (b2), the carbon nanotube segments 143 having a predeterminedwidth can be selected by using an adhesive tape as the tool to contactthe carbon nanotube array. Each carbon nanotube segment 143 includes aplurality of carbon nanotubes parallel to each other. In step (b2), thepulling direction is substantially perpendicular to the growingdirection of the carbon nanotube array.

More specifically, during the pulling process, as the initial carbonnanotube segments 143 are drawn out, other carbon nanotube segments 143are also drawn out end to end due to van der Waals attractive forcebetween ends of adjacent carbon nanotube segments 143. This process ofdrawing ensures a substantially continuous and uniform drawn carbonnanotube film having a predetermined width can be formed. Referring toFIG. 5, the drawn carbon nanotube film includes a plurality of carbonnanotubes 145 joined ends to ends. The carbon nanotubes 145 in the drawncarbon nanotube film are all substantially parallel to thepulling/drawing direction of the drawn carbon nanotube film, and thedrawn carbon nanotube film produced in such manner can be selectivelyformed to have a predetermined width. The drawn carbon nanotube filmformed by the pulling/drawing method has superior uniformity ofthickness and conductivity over many carbon nanotube films. Further, thepulling/drawing method is simple, fast, and suitable for industrialapplications. The drawn carbon nanotube film can be cut into desiredlengths and widths. They can also be placed side by side to createlarger films.

It is noted that because the carbon nanotubes in the carbon nanotubearray have a high purity and a high specific surface area, the carbonnanotube film is adhesive in nature. As such, the at least one drawncarbon nanotube film can be directly adhered to the surfaces of thefirst substrate 120, the second substrate 140, and/or another drawncarbon nanotube film. In the alternative, other bonding means can beapplied. To form one carbon nanotube structure having a plurality ofcarbon nanotube films therein, the carbon nanotube films can stacked oneach other.

An additional step of treating the drawn carbon nanotube films with anorganic solvent after the drawn carbon nanotube films are adhered on thefirst and second substrates 120, 140 can be further provided.Specifically, the drawn carbon nanotube films can be treated by applyingorganic solvent to the drawn carbon nanotube films to soak the entiresurfaces of the drawn carbon nanotube films. The organic solvent isvolatile and can be selected from the group consisting of ethanol,methanol, acetone, dichloroethane, chloroform, and any appropriatemixture thereof. Here, the organic solvent is ethanol. After beingsoaked by the organic solvent, microscopically, carbon nanotube stringswill be formed by adjacent carbon nanotubes in the drawn carbon nanotubefilm, that are able to do so, bundling together, due to the surfacetension of the drying organic solvent. In one aspect, some and/or partsof the carbon nanotubes in the untreated drawn carbon nanotube film thatare not adhered on the first and second substrates 120,140 will comeinto contact with the first and second substrates 120,140 after theorganic solvent treatment due to the surface tension of the organicsolvent. Then the contacting area of the drawn carbon nanotube filmswith the first and second substrates 120,140 will increase, and thus,the drawn carbon nanotube films can be firmly adhered to the first andsecond substrates 120,140. In another aspect, due to the decrease of thespecific surface area via bundling, the mechanical strength andtoughness of the drawn carbon nanotube films are increased and thecoefficient of friction of the drawn carbon nanotube films is reduced.Macroscopically, the treated drawn carbon nanotube films will still looklike uniform films.

In one embodiment, at least one of the first transparent electrodes 122and the second transparent electrodes 142 can include a transparentcarbon nanotube composite structure. The carbon nanotube compositestructure includes one or a plurality of carbon nanotube films.Referring to FIG. 7, an embodiment of the first and second transparentelectrodes 122 and 142, the carbon nanotube composite structure includesthe above-described drawn carbon nanotube film and a polymer materialinfiltrated in the drawn carbon nanotube film. It is to be understoodthat spaces exist between the adjacent carbon nanotubes in the carbonnanotube film, and thus the carbon nanotube film includes a plurality ofmicropores defined by the adjacent carbon nanotubes therein. The polymermaterial is filled into the micropores in the carbon nanotube film toform the carbon nanotube composite structure. The carbon nanotube filmcan be disordered carbon nanotube film or ordered carbon nanotube film.Here, the carbon nanotube film is ordered carbon nanotube film.

Similar to the carbon nanotube structure, a thickness of the carbonnanotube composite structure can be set as an acceptable transparency ofthe carbon nanotube composite structure is acquired. As shown in FIG. 7,the thickness of the carbon nanotube composite structure is in the rangefrom about 0.5 nanometers to 1 millimeter. The carbon nanotube compositestructure has substantially uniform thickness.

The polymer material is transparent and can be selected from the groupconsisting of polycarbonate (PC), polymethyl methacrylate acrylic(PMMA), polyethylene terephthalate (PET), benzocyclobutenes (BCB),polystyrene, polyethylene, polycarbonate, polycycloolefins, and anyother suitable materials. Here, the polymer material is PMMA.

The polymer material can also combine the carbon nanotube compositestructure with the first substrate 120 and the second substrate 140firmly. Accordingly, the life-span of the touch panel 10 is improved.Referring to FIG. 8, due to the polymer material infiltrated into thedrawn carbon nanotube film, unwanted short circuits in the carbonnanotube structure are eliminated, and thus the carbon namotubecomposite layer has a good linearity of the resistance to the distance.Accordingly, the accuracy of the touch panel 10 can be improved.

It is to be understood that, the carbon nanotube composite structure canbe composed by the plurality of carbon nanotube composite films disposedside by side or stacked with each other. The carbon nanotube compositefilm can be formed by each carbon nanotube film infiltrated by thepolymer material or having the entire carbon nanotube structureinfiltrated by the polymer material.

In one embodiment, each of the first transparent electrodes 122 and thesecond transparent electrodes 142 includes the carbon nanotube compositestructure. The carbon nanotube composite structure includes one drawncarbon nanotube film infiltrated by the PMMA. The carbon nanotubes inthe first transparent electrodes 122 are aligned along the firstdirection. The carbon nanotubes in the second transparent electrodes 142are aligned along the second direction.

In one embodiment, the carbon nanotube composite structure is formed byhaving the first substrate 120 and second substrate 140 coated with alayer of polymer material solution. Then, the drawn carbon nanotubefilms are laid on the layer of polymer material solution. After that, apressure is applied on the drawn carbon nanotube film to make thepolymer material solution infiltrate into the carbon nanotube film.Finally, the polymer material solution is solidified by a heating step.A wind knife with a wind force of 10 meters per second (m/s) to 20 m/scan be used to blow the carbon nanotube film. The carbon nanotube filmis pressed into the layer of polymer material solution, and themicropores of the carbon nanotube film are filled with the polymermaterial solution by the wind force. The carbon nanotube film has athickness of about 0.5 nm to about 100 mm.

The polymer material solution can be made of an organic solvent and thepolymer material dissolved in the organic solvent. The polymer materialsolution can be in liquid state and adhesive, and thus the polymermaterial solution can be adhered directly on the first substrate 120 toform the layer of the polymer material solution on the first substrate120. In one embodiment, the viscosity of the polymer material solutionis greater than 1 Pascal second (Pa sec). The polymer material istransparent and is a solid in room temperature. The polymer material canbe selected from the group consisting of polycarbonate (PC), polymethylmethacrylate acrylic (PMMA), polyethylene terephthalate (PET),benzocyclobutenes (BCB), polystyrene, polyethylene, polycarbonate, andpolycycloolefins and any other suitable materials. The organic solventis volatile at room temperature, and can be selected from the groupconsisting of ethanol, methanol, acetone, dichloroethane, chloroform,and combinations thereof. The organic solvent can be eliminated by theheating step. In one embodiment, the polymer material is PMMA, thepolymer material solution is the solution of PMMA in ethanol. It is tobe understood that, the carbon nanotube wires can be used in the firstand/or second signal wires 124, 144, and the carbon nanotube wires canbe made by the drawn carbon nanotube films. The carbon nanotube wire canbe twisted or untwisted. The untwisted carbon nanotube wire can beformed by treating the drawn carbon nanotube film with an organicsolvent. Specifically, the drawn carbon nanotube film is treated byapplying the organic solvent to the carbon nanotube film to soak thesurface of the drawn carbon nanotube film without being adhered on asubstrate. After being soaked by the organic solvent, the adjacentparalleled carbon nanotubes in the drawn carbon nanotube film willbundle together, due to the surface tension of the organic solvent whenthe organic solvent volatilizing, and thus, the drawn carbon nanotubefilm will be shrunk into untwisted carbon nanotube wire. The organicsolvent is volatile. The twisted carbon nanotbue wire can be formed bytwisting a drawn carbon nanotube film by using a mechanical force toturn the two ends of the drawn carbon nanotube film in oppositedirections.

Further, a filling layer 160 can be further located in gaps between theadjacent first transparent electrodes 122 and the adjacent secondtransparent electrodes 142 to improve the visual appearance of the touchpanel 100. The filling layer 160 can be made of a material with arefractive index and a transmissivity similar to that of the first andsecond transparent electrodes 122, 142.

The sensor 182 is used for detecting the corresponding first transparentelectrode 122 driven by the X-coordinate drive power source 180 and thecorresponding second transparent electrode 142 driven by theY-coordinate drive power source 184 when a variation of the voltage isoccurred.

An insulative layer 18 can be further provided between the first and thesecond electrode plates 12 and 14, and located around edges of thesecond surface 148 of the second substrate 140. The first electrodeplate 12 is located on the insulative layer 18. The insulative layer 18can seal the gap between the first electrode plate 12 and the secondelectrode plate 14. The first transparent electrodes 122 are oppositeto, and spaced from the second transparent electrodes 142. The dotspacers 16, if used, can be located on the second transparent electrodes142. A distance between the second electrode plate 14 and the firstelectrode plate 12 can be in an approximate range from 2 to 20 microns.The insulative layer 18 and the dot spacers 16 are made of, for example,insulative resin or any other suitable insulative material. Insulationbetween the first electrode plate 12 and the second electrode plate 14is provided by the insulative layer 18 and the dot spacers 16 when thetouch panel 10 is not in use. It is to be understood that the dotspacers 16 are optional, particularly when the touch panel 10 isrelatively small. The dot spacers 16 serve as supports given the size ofthe span and the strength of the first electrode plate 12.

A transparent protective film 150 can be further located on the topsurface of the touch panel 10. The transparent protective film 150 canbe a film that receives a surface hardening treatment to protect thefirst electrode plate 12 from being scratched when the touch panel 10 isin use. The transparent protective film 150 can be plastic or resin.

The touch panel 10 can further include a shielding layer 152 located onthe lower surface of the second substrate 140. The material of theshielding layer 152 can be selected from a group consisting of indiumtin oxide, antimony tin oxide, carbon nanotube film, and otherconductive materials. In one embodiment, the shielding layer 152 is acarbon nanotube film. The shielding layer 152 is connected to ground andplays a role of shielding and, thus, enables the touch panel 10 tooperate without interference (e.g., electromagnetic interference).Furthermore, a passivation layer 154 can be located on a surface of theshielding layer 152, on the side away from the second substrate 140. Thematerial of the passivation layer 154 can, for example, be siliconnitride or silicon dioxide. The passivation layer 154 can protect theshielding layer 152 from chemical or mechanical damage.

As shown in FIG. 4, the touch panel 10 can further includes a controller190 that incorporates the X-coordinate drive power source 180, sensor182, Y-coordinate drive power source 184, and a grounded point. Thecontroller 190 acquires the data from the first and second transparentelectrodes 122, 142. In one embodiment, the controller 190 may include astorage element for storing a touch screen program, which is capable ofcontrolling different aspects of the touch panel 10 and is configuredfor sending raw data to a processor so that the processor processes theraw data. For example, the processor receives data from the controller190 and determines how the data is to be used within a electronicapparatuses adopting the touch panel 10. The data may include thecoordinates of each touching point as well as the pressure exerted oneach touching point. In another embodiment, the controller 190 isconfigured for processing the raw data itself. That is, the controller190 reads the pulses from the first and second transparent electrodes122, 142 and turns them into data that the processor can understand. Thecontroller 190 may perform filtering and/or conversion processes.Filtering process is typically implemented to reduce a busy data streamso that the processor is not overloaded with redundant or non-essentialdata. The conversion processes may be implemented to adjust the raw databefore sending or reporting them to the processor.

The conversions may include determining the center point for each touchregion. In use, when several fingers, such as four, or several stylusestouch or scratch the surface of the touch panel 10 at almost the sametime, four contact points T1-T4 can be formed between the firsttransparent electrodes 122 and the second transparent electrodes 142 atthe same time. Then four separated signals S1-S4 for each touch pointT1-T4 that occurs on the surface of the touch panel 10 at the same timeare tracked. The number of recognizable touches can be about 15. 15touch points allows for all 10 fingers, two palms and 3 others. Thetouch panel 10 recognizes the touch events on the surface thereof andthereafter output this information to the processor. The processorinterprets the touch events and thereafter actions based on the touchevents. Specifically, the X-coordinate drive power source 180 applyvoltages on the first transparent electrodes 122 one by one in separatetime, and the Y-coordinate drive power source 184 apply voltages on thesecond transparent electrodes 142 one by one in separate time. A usertouches or presses the top surface of the touch panel 10. The firstelectrode plate 12 is curved and the first transparent electrode 122 atthe pressed position is in connecting with the second transparentelectrode 142. The second ends 142 b of the second electrodes 142 aregrounded, and thus the sensor 182 can detect the corresponding firsttransparent electrode 122 driven by the X-coordinate drive power source180 and the corresponding second transparent electrode 142 driven by theY-coordinate drive power source 184 when a variation of the voltage isoccurred. The coordinates X and Y of the pressed position is thendetected.

When more than one point on the touch panel 10 are pressed at the sametime, the first transparent electrodes 122 at more than one pressedlocations are in connecting with the second transparent electrodes 142.Due to the X-coordinate drive power source 180 and Y-coordinate drivepower source 184 applying voltages on the first transparent electrodes122 and the second transparent electrodes 142 one by one in separatetime, the sensor 182 can one-by-one detect all the corresponding firsttransparent electrodes 122 driven by the X-coordinate drive power source180 and all the corresponding second transparent electrodes 142 drivenby the Y-coordinate drive power source 184 when variations of thevoltages are occurred. The coordinates X and Y of the pressed positionsare then detected.

The multiple touch events can be separately or together to performsingular or multiple actions in the electronic apparatuses. When usedseparately, a first touch event may be used to perform a first actionwhile a second touch event may be used to perform a second action thatis different than the first action. The actions may for example includemoving an object such as a cursor or pointer scrolling or panning,adjusting control settings, opening a file or document, viewing a menu,making a selection executing instructions, operating a peripheral deviceconnected to the electronic apparatuses. When used together, first andsecond touch events may be used for performing one particular action.The particular action may for example include logging onto a computer ora computer network, permitting authorized individuals access torestricted areas of the computer or computer network, loading a userprofile associated with a user's preferred arrangement of the computerdesktop, permitting access to web content, launching a particularprogram, encrypting or decoding a message, and/or the like.

The touch panel 10 can be disposed on a display device. The displaydevice can be a monochrome display, color graphics adapter (CGA)display, enhanced graphics adapter (EGA) display,variable-graphics-array (VGA) display, super VGA display, liquid crystaldisplay (LCD), cathode ray tube (CRT), plasma displays and the like. Thedisplay device with the touch panel 10 thereon is operatively coupled tothe processor and may be a separated component (peripheral device) or beintegrated with the processor and program storage to form a desktopcomputer (all in one machine), a laptop, handheld or tablet or the like.

Referring to the embodiment of FIG. 9, a liquid crystal display screen300 using the above mentioned touch panel 10 is disclosed. The liquidcrystal display screen 300 includes an upper board 100, a lower board200 opposite to the upper board 100, and a liquid crystal layer 310located between the upper board 100 and the lower board 200.

A thickness of the liquid crystal layer 310 can be about 1 micron toabout 50 microns. In one embodiment, the thickness of the liquid crystallayer 310 is about 5 microns. The liquid crystal layer 310 includes aplurality of cigar shaped liquid crystal molecules. Understandably, theliquid crystal layer 310 can also be made of other suitable materials.The liquid crystal molecules can vary aligned directions thereof underdifferent electrical fields.

The upper board 100 from top to bottom includes the touch panel 10, afirst polarizing layer 110, and a first alignment layer 112. The firstpolarizing layer 110 is disposed directly on the lower surface of thesecond substrate 140 of the touch panel 10. The first alignment layer112 is disposed on the lower surface of the first polarizing layer 110.A lower surface of the first alignment layer 112 is adjacent to theliquid crystal layer 310. The lower surface of the first alignment layer112 can further define a plurality of parallel straight first grooves(not shown). The first grooves are configured to align the orientationof the liquid crystal molecules.

The first polarizing layer 110 can be made of dichroic/dichromaticmaterial. One typical type of dichroic polarizing layer 110 is made byincorporating a dye into a polymer matrix, which is stretched in atleast one direction. The diebroic polarizers can also be made byuniaxially stretching a polymer matrix and staining the matrix with adichroic dye. Alternatively, a polymer matrix can be stained with anoriented dichroic dye. The dichroic dyes generally include anthraquinoneand azo dyes, as well as iodine. In other embodiments, the firstpolarizing layer 110 can be made of at least one drawn carbon nanotubefilm. The drawn carbon nanotube films are aligned along a samedirection. The carbon nanotubes in the first polarizing layer 110 aresubstantially aligned along the same direction. The carbon nanotubeshave uniform absorption ability in the entire electromagnetic wavelengthregion, thus the first polarizing layer 110 made of drawn carbonnanotube film has a uniform polarization property in the entireelectromagnetic wavelength region. When light beams are transmitted intoa front side of the first polarizing layer 110, the light beams having apolarization parallel to the carbon nanotubes are absorbed by the carbonnanotubes, and the light beams having a polarization normal to thecarbon nanotubes are transmitted through the first polarizing layer 110.Accordingly, the polarized light beams are transmitted through the firstpolarizing layer 110. The thickness of the first polarizing layer 110can be ranged from about 1 micron to 0.5 millimeters.

Further, it is to be understood that in the liquid crystal displayscreen 300, an upper electrode (not shown) is needed to cooperate with alower electrode (i.e., the pixel electrode) to apply a voltage on theliquid crystal layer located between the upper electrode and the lowerelectrode. In one embodiment, the upper electrode is disposed betweenthe first alignment layer 112 and the first polarizing layer 110. Thefirst polarizing layer 110 can be the drawn carbon nanotube film.Therefore, in another embodiment, the first polarizing layer 110 made bythe drawn carbon nanotube film and can be used as the upper electrode inthe liquid crystal display screen 300. Thus the first polarizing layer110, made by the drawn carbon nanotube film, functions as the upperelectrode as well as polarizing layer. In this situation, the upperelectrode is needless. The resulting liquid crystal display screen 300is thinner and requires fewer elements, but retains the same function.

The material of the first alignment layer 112 can be selected from agroup consisting of polystyrene and its derivatives, polyimide,polyvinyl alcohol, polyester, epoxy resin, polyurethane, polysilane, andother suitable materials. The first grooves can be made by a scratchingmethod, a SiOx-depositing method, or a micro grooves treating method. Inone embodiment, the first alignment layer 112 is made of polyurethaneand has a thickness of about 1 micron to about 50 microns.

It is to be understood that, in the drawn carbon nanotube film, thecarbon nanotubes are aligned along the same direction and a groove canbe formed by two adjacent carbon nanotubes. Thus, in another embodiment,the first polarizing layer 110 made of drawn carbon nanotube film andcan serve as the first alignment layer 112 as well. In otherembodiments, the drawn carbon nanotube film is used as the alignmentlayer 112, while still employing a first polarizing layer 110. The drawncarbon nanotube films are aligned along a same direction, and the carbonnanotubes in the first alignment layer 112 are aligned substantiallyalong the same direction. The lower board 200 from top to bottomincludes a second alignment layer 212, a thin film transistor panel 220,and a second polarizing layer 210. The second alignment layer 212 isdisposed on an upper surface of the thin film transistor panel 220 andadjacent to the liquid crystal layer 310. The second polarizing layer210 is disposed on a lower surface of the thin film transistor panel220. The second alignment layer 212 can further include a plurality ofparallel straight second grooves. A length direction of the firstgrooves is perpendicular to a length direction of the second grooves.The second polarizing layer 210 can be made of dichroic/dichromaticmaterial or the drawn carbon nanotube film as the above-described firstpolarizing layer 110. The thickness of the second polarizing layer 210can be ranged from about 1 micron to 0.5 millimeters. The secondpolarizing layer 210 is for polarizing the light emitted from aback-light unit disposed under the liquid crystal display screen 300,and achieving a polarized light. A polarizing direction of the secondpolarizing layer 210 is perpendicular to a polarizing direction of thefirst polarizing layer 110. When the second polarizing layer 210includes at least one layer of the drawn carbon nanotube film, thecarbon nanotubes in the second polarizing layer 210 are substantiallyaligned along a same direction and perpendicular to the carbon nanotubesin the first polarizing layer 110. The material of the second alignmentlayer 212 can be selected from a group consisting of polystyrene and itsderivatives, polyimide, polyvinyl alcohol, polyester, epoxy resin,polyurethane, polysilane, and other suitable materials. In oneembodiment, the second alignment layer 212 is made of polyurethane andhas a thickness of about 1 micron to about 50 microns. In otherembodiments, the second alignment layer 212 can include at least onelayer of the drawn carbon nanotube film as the described herein. Thedrawn carbon nanotube films are aligned along a same direction, and thecarbon nanotubes in the second alignment layer 212 are alignedsubstantially along the same direction. When the first and secondalignment layers 112, 212 both include the drawn carbon nanotube film,the carbon nanotubes in the first alignment layer 112 are perpendicularto the carbon nanotubes in the second alignment layer 212.

In one embodiment, the aligned direction of the carbon nanotubes in thefirst alignment layer 112 is the same with the aligned direction of thecarbon nanotubes in the first polarizing layer 110, and is defined asthe third direction. The aligned direction of the carbon nanotubes inthe second alignment layer 212 is the same with the aligned direction ofthe carbon nanotubes in the second polarizing layer 210, and is definedas the fourth direction. The third direction is perpendicular to thefourth direction. Due to the length direction of the first grooves onthe first alignment layer 112 being perpendicular to the lengthdirection of the second grooves on the second alignment layer 212, thealigned direction of the liquid crystal molecules are turned 90 degreesfrom the first alignment layer 112 to the second alignment layer 212.

Referring to the embodiment shown in FIG. 10, the thin film transistorpanel 220 includes a third substrate 240, a plurality of thin filmtransistors 222, a plurality of pixel electrodes 224, a plurality ofsource lines 226, and a plurality of gate lines 228. The thin filmtransistors 222, pixel electrodes 224, source lines 226, and gate lines228 are disposed on a same surface (upper surface) of the thirdsubstrate 240. The source lines 226 are spaced from each other and canbe arranged parallel along X direction. The gate lines 228 are spacedfrom each other and can be arranged parallel along Y direction. The Ydirection is perpendicular to the X direction. Thus, the surface of theinsulating substrate 240 is divided into a matrix of grid regions 242.The pixel electrodes 224 and the thin film transistors 222 areseparately disposed in the grid regions 242. The pixel electrodes 224are spaced from each other. The thin film transistors 222 are spacedfrom each other. Each grid region 242 contains one thin film transistor222 and one pixel electrode 224 stacked or spaced apart from each other.Here, in each grid region 242, the pixel electrode 224 covers the thinfilm transistor 222. Referring to FIG. 11, the thin film transistor 222,according to one embodiment, includes a semiconducting layer 2220, asource electrode 2222, a drain electrode 2224, an insulating layer 2226,and a gate electrode 2228.

The pixel electrode 224 is electrically connected with the drainelectrode 2224 of the thin film transistor 222. More specifically, apixel insulating layer 244 can be further disposed on the thin filmtransistor 222. The pixel insulating layer 244 covers the thin filmtransistor 222 and defines a through hole 246 to expose the drainelectrode 2224 of the thin film transistor 222. The pixel electrode 224covers the entire grid region 242 and the thin film transistor 222therein, and electrically connects to the drain electrode 2224 at thethrough hole 246. Other part of the thin film transistor 222 except thedrain electrode 2224 is insulated from the pixel electrode 224 by thepixel insulating layer 244. The material of the pixel insulating layer244 can be a rigid material such as silicon nitride (Si3N4) or silicondioxide (SiO2), or a flexible material such as polyethyleneterephthalate (PET), benzocyclobutenes (BCB), or acrylic resins.

Each source electrode 2222 of the thin film transistor 222 iselectrically connected with one source line 226. More specifically, thesource electrodes 2222 of each line of the thin film transistors 222 areelectrically connected with one source line 226 near the thin filmtransistors 222. Each gate electrode 2228 of the thin film transistor222 is electrically connected with one gate line 228. The gateelectrodes 2228 of each line of the thin film transistors 222 areelectrically connected with one gate line 228 near the thin filmtransistors 222.

The thin film transistor panel 220 can further include a drive circuit(not shown). The source lines 226 and gate lines 228 are connected tothe drive circuit. The drive circuit controls the on and off of the thinfilm transistors 222 through the source lines 226 and gate lines 228.The drive circuit can be mounted on the third substrate 240.

The third substrate 240 is provided for supporting the thin filmtransistor 222. The material of the third substrate 240 can be the sameas a substrate of a printed circuit board (PCB), and can be selectedfrom rigid materials (e.g., p-type or n-type silicon, silicon with ansilicon dioxide layer formed thereon, glass, crystal, crystal with aoxide layer formed thereon), or flexible materials (e.g., plastic orresin). In one embodiment, the material of the insulating substrate isPET.

The pixel electrodes 224 are transparent conductive films made of aconductive material. When the pixel electrodes 224 is used in the liquidcrystal displays, the materials of the pixel electrodes 224 can beselected from the group consisting of indium tin oxide (ITO), antimonytin oxide (ATO), indium zinc oxide (IZO), conductive polymer, andmetallic carbon nanotubes. An area of each pixel electrode 224 can be ina range from about 10 square micrometers to 0.1 square millimeters. Inone embodiment, the material of the pixel electrode 224 is ITO, the areaof each pixel electrode 224 is about 0.05 square millimeters.

The materials of the source lines 226 and the drain lines 140 areconductive, and can be selected from the group consisting of metal,alloy, silver paste, conductive polymer, or metallic carbon nanotubewires. The metal or alloy can be selected from the group consisting ofaluminum (Al), copper (Cu), tungsten (W), molybdenum (Mo), gold (Au),titanium (Ti), neodymium (Nd), palladium (Pd), cesium (Cs), andcombinations thereof. A width of the source lines 226 and the gate lines228 can be in the range from about 0.5 nanometers to about 100micrometers. Here, the material of the source lines 226 and the gatelines 228 is Al, the width of the source lines 226 and the gate lines228 is about 10 micrometers.

The thin film transistor 222 can be a top gate structure or a bottomgate structure. Referring to the embodiment shown in FIG. 11, the thinfilm transistor 222 is a bottom gate structure. The gate electrode 2228is disposed on the upper surface of the third substrate 240. Theinsulating layer 2226 covers the gate electrode 2228. The semiconductinglayer 2220 is disposed on the insulating layer 2226, and insulated fromthe gate electrode 2228 by the insulating layer 2226. The sourceelectrode 2222 and the drain electrode 2224 are spaced apart from eachother and electrically connected to the semiconducting layer 2220. Thesource electrode 2222, and the drain electrode 2224 are insulated fromthe gate electrode 2228 by the insulating layer 2226. The semiconductinglayer 2220 can be made of semiconducting material such as amorphoussilicone (a-Si), poly-silicone (p-Si), or organic semiconductingmaterial. A length of the semiconducting layer 2220 is ranged from about1 micron to 100 microns. A width of the semiconducting layer 2220 isranged from about 1 micron to 1 millimeter. A thickness of thesemiconducting layer 2220 is ranged from about 0.5 nanometers to 100microns.

The semiconducting layer 2220 includes a semiconducting carbon nanotubestructure. The semiconducting carbon nanotube structure includes aplurality of single-walled carbon nanotubes or double-walled carbonnanotubes having semi-conducting carbon nanotubes. Diameters of thesingle-walled carbon nanotubes range from about 0.5 nanometers to about50 nanometers. Diameters of the double-walled carbon nanotubes rangefrom about 1 nanometer to about 50 nanometers. In one embodiment, thecarbon nanotubes are single-walled carbon nanotubes with the diametersless than 10 nanometers.

More specifically, the semiconducting carbon nanotube structure caninclude the ordered carbon nanotube film or disordered carbon nanotubefilm as described above. In the embodiment shown in FIG. 12, thesemiconducting carbon nanotube structure includes an ordered carbonnanotube film. Referring to FIG. 12, a carbon nanotube segment filmincludes a plurality of carbon nanotubes arranged along one orientation.The carbon nanotubes are parallel with each other, have almost equallength and are combined side by side by van der Waals attractive forcetherebetween. A length of the carbon nanotubes can reach up to severalmillimeters. The length of the carbon nanotube segment film can be equalto the length of all the carbon nanotubes, such that at least one carbonnanotube will span the entire length of the carbon nanotube segmentfilm. The length of the carbon nanotube segment film is only limited bythe length of the carbon nanotubes. The length of the carbon nanotubescan range from about 1 millimeter to about 10 millimeters.

In some embodiments, the ordered carbon nanotube segment film can beproduced by growing a strip-shaped carbon nanotube array, and pushing(or pressing) the strip-shaped carbon nanotube array down along adirection perpendicular to length of the strip. The strip-shaped carbonnanotube array is grown from a substrate where a strip-shaped catalystfilm is formed. The strip-shaped catalyst film has a relatively longlength, and a relatively narrow width less than 20 micrometers. A heightof the carbon nanotube array can range from about 1 millimeter to about10 millimeters.

The strip-shaped carbon nanotube array can be pushed down by the actionof an organic solvent. The trip-shaped carbon nanotube array can beimmersed into the organic solvent; and elevated from the organic solventalong a direction perpendicular to the length of the strip. The stripsof carbon nanotubes are forced down on the substrate because of thesurface tension of the organic solvent to form the carbon nanotubesegment film.

The strip-shaped carbon nanotube array can be pushed down by amechanical force executed by a pressing device. The pressing devicepresses the strip-shaped carbon nanotube array along a directionparallel to perpendicular to the length of the strip. The pressingdevice can be, e.g., a pressure head with a glossy surface, such as aroller. The strip-shaped carbon nanotube array can be pushed down by anair current blowing. The strip-shaped carbon nanotube array is blowndown on the substrate along a direction parallel to perpendicular to thelength of the strip. It is also understood that a carbon nanotube filmcan be made from many strip-shaped carbon nanotube arrays, aligned suchthat the length of the carbon nanotubes are less than the distancebetween adjacent strips. When the strips are pressed down, adjacentcarbon nanotubes overlap. In some embodiments, the carbon nanotube filmcan be produced by a method adopting a “kite-mechanism” and can havecarbon nanotubes with a length of even above 10 centimeters. This isconsidered by some to be ultra-long carbon nanotubes. However, thismethod can be used to grow carbon nanotubes of many sizes. Specifically,the carbon nanotube film can be produced by a method includes thefollowing steps. Firstly, a growing substrate with a catalyst layerlocated thereon is provided. Secondly, the growing substrate is placedadjacent to the insulating substrate in a chamber. Then the chamber isheated to a growth temperature for carbon nanotubes a protective gastherein, and is introduced a carbon source gas along a gas flowdirection. After introducing the carbon source gas into the chamber, thecarbon nanotubes starts to grow. One end (e.g., the root) of the carbonnanotubes is fixed on the growing substrate. The growing substrate isnear an inlet of the introduced carbon source gas, the ultralong carbonnanotubes float above the insulating substrate with the roots of theultralong carbon nanotubes still attached to the growing substrate. Thelength of the ultralong carbon nanotubes depends on the growthconditions. After growth has been stopped, the ultralong carbonnanotubes land on the insulating substrate. The carbon nanotubes arethen separated from the growing substrate. Thus, a plurality of carbonnanotubes can be formed on the insulating substrate. This can berepeated many times so as to obtain many layers of carbon nanotubes on asingle insulating substrate. The insulating substrate can be rotatedafter each cycle such that the adjacent layers may have an angle from 0to less than or equal to 90 degrees.

It is to be understood that, to achieve the semiconducting layer 2220,the carbon nanotube segment film can be further treated by an additionalstep of eliminating the metallic carbon nanotubes therein. In oneembodiment, the step can be performed by applying a voltage between thesource electrode 2222 and the drain electrode 2224, to break down themetallic carbon nanotubes in the carbon nanotube segment layer connectedtherebetween, and thereby achieving a semiconducting layer 2220 free ofmetallic carbon nanotubes therein. The voltage is in a range from 1 to1000 volts (V). In other embodiments, the step can be performed byirradiating the carbon nanotube segment layer with a hydrogen plasma,microwave, terahertz (THz), infrared (IR), ultraviolet (UV), or visiblelight (Vis), to break down the metallic carbon nanotubes in the carbonnanotube segment layer, and thereby achieving the semiconducting layer2220 free of metallic carbon nanotubes therein.

The semiconducting layer 2220 can have a length of about 50 microns, awidth of about 300 microns, and a thickness of about 5 nanometers. Achannel is defined in the semiconducting layer 2220 between the sourceelectrode 2222 and the drain electrode 2224. The channel can have alength of about 5 microns and a width of about 40 microns to 100microns. In the semiconducting layer 2220, two ends of each carbonnanotubes are connected to the source electrode 2222 and the drainelectrode 2224. The carrier mobility of the semiconducting carbonnanotubes along the length direction thereof is relatively high, and thecarbon nanotubes in the semiconducting carbon nanotube structure arealigned substantially from the source electrode 2222 to the drainelectrode 2224. Therefore, the travel path of the carriers in thesemiconducting layer 2220 is minimal, and the carrier mobility of thethin film transistor 222 is relatively high. Referring to FIGS. 10 and13, in use, the drive circuit applies a scanning voltage to the sourcelines 226, and applies a controlling voltage on the gate lines 228. Thesource electrode 2222 and the drain electrode 2224 are electricallyconnected, and a voltage is applied on the pixel electrode 224 connectedto the drain electrode 2224. When the voltage is applied on the pixelelectrode 224, the electric field between the pixel electrode 224 andthe first polarizing layer 110 comprising the drawn carbon nanotube filmforces the liquid crystal molecules to align vertically, and thus thelight polarized by the second polarizing layer 210 goes through theliquid crystal layer 310 without being twisted, and is stopped by thefirst polarizing layer 110. When the voltage is not applied on the pixelelectrode 224, the light polarized by the second polarizing layer 210 istwisted by the liquid crystal molecules and can emit through the firstpolarizing layer 110.

Referring to FIG. 14, the liquid crystal display screen 300 can furtherinclude a first controller 40, a central processing unit (CPU) 50, and asecond controller 60. The touch panel 10 is connected to the firstcontroller 40 by an external circuit. The first controller 40, the CPU50, and the second controller 60 are electrically connected. The drivecircuit of the thin film transistor panel 220 is electrically connectedto the second controller 60.

A user operates the display by pressing the first electrode plate 12 ofthe touch panel 10 with a finger, a pen 60, or the like while visuallyobserving the displaying of the liquid crystal display screen 300through the touch panel 10. This pressing causes a deformation of thefirst electrode plate 12 at a pressed position 70. As discussed abovethe multi touch panel 10 can receive single or multiple coordinates ofareas being touched. These X and Y coordinate(s) are received by thefirst controller 40.

Changes in voltages in the first direction of the first conductive layer142 and the second direction of the second transparent electrode 142 canbe detected by the first controller 40. Then, the first controller 40transforms the changes in voltages into coordinates of the pressingposition and sends the coordinates to the CPU 50. The CPU 50 then sendsout commands according to the coordinates of the pressing position andcontrols the working of the thin film transistor panel 220 by the secondcontroller 60.

The liquid crystal display screen 300 can be used in electronicapparatuses, such as personal computer systems (e.g., desktops, laptops,tablets or handhelds). The electronic apparatuses may also correspond topublic computer systems such as information kiosks, automated tellermachines (ATM), point of sale machines (POS), industrial machines,gaming machines, arcade machines, vending machines, airline e-ticketterminals, restaurant reservation terminals, customer service stations,library terminals, learning devices, and the like. The CPU of theelectronic apparatuses and the CPU 50 of the liquid crystal displayscreen 300 can be integrated. Further, to keep the distance from theupper board 100 to the lower board 200, a plurality of spacers (notshown) can be disposed between the upper board 100 and the lower board200. In one embodiment, a diameter of the spacers is in the range fromabout 1 micron to about 10 microns.

It is to be understood that the liquid crystal display screen 300 canfurther include other elements such as color filters, black matrix,backlight unit, TFT driving circuit unit, and so on. The color filtersare disposed below the first polarizing layer 110 for providingdifferent color of lights. The black matrix is formed on the lowersurface of the second substrate 140. The backlight unit is disposedbelow the second polarizing layer 210 for providing light. The TFTdriving circuit unit is connected to the TFTs for driving the TFT panel220. The black matrix may be located on the lower surface of the secondsubstrate 140 in a matrix arrangement. The black matrix may divide thesurface of the second substrate 140 into a plurality of cell areas wherethe color filters are to be formed and to prevent light interferencebetween adjacent cells. The color filter may include red, green, andblue tricolors.

The touch panel 10, liquid crystal display screen 300 using the same,and the methods for making the same in the embodiments can have thefollowing superior properties. The touch panel 10 adopting the pluralityof the first and second transparent electrodes 122, 142 can sense aplurality touches or presses occurred at the same time. The propertiesof the carbon nanotubes provide superior toughness and high mechanicalstrength to the carbon nanotube film and further to the carbon nanotubestructure. Thus, the touch panel 10 and the liquid crystal displayscreen 300 using the same adopting the carbon nanotube structure aredurable and highly reliable. In embodiments employing the drawn carbonnanotube film is flexible, and suitable for using as the first andsecond transparent electrodes 122, 142 in a flexible touch panel 10. Thepulling method for fabricating each drawn carbon nanotube film issimple, and the adhesive drawn carbon nanotube film can be laid on thesubstrates 120, 140, 240 directly. As such, the drawn carbon nanotubefilm is suitable for the mass production of touch panels 10 and liquidcrystal display screen 300 using the same. The drawn carbon nanotubefilm has a high transparency, thereby improving brightness of the touchpanel 10 and the liquid crystal display screen 300 using the same. Thedrawn carbon nanotube film has the properties of light polarizing andelectrically conducting, and thus the drawn carbon nanotube film can beused as both the first polarizing layer 110 and the upper electrode inone structure. Accordingly, the resulting embodiments can have a simplerstructure, thinner thickness, and higher brightness. In embodimentsemploying carbon nanotubes in the semiconducting layer 2220 of the thinfilm transistor 222, the flexibility of the thin film transistor 222 canbe improved. To cooperate with other flexible material, the liquidcrystal display screen 300 can also be made flexible. The semiconductingcarbon nanotube structure is adhesive and can be easily adhered on adesired location at a low temperature (e.g., room temperature). Thus,the semiconducting carbon nanotube structure can be transfer-printed onthe insulating layer 2226, and the thin film transistor 222 can be madeat low temperature.

It is to be understood that there are two kinds of carbon nanotubes:metallic carbon nanotubes and semiconducting carbon nanotubes determinedby the arrangement of the carbon atoms therein. The carbon nanotubestructure or carbon nanoatube film may contain both kinds of the carbonnanotubes. In the present application, only in the semiconducting layers2220, almost all or at least a large part of the carbon nanotubes aresemiconducting carbon nanotubes. In other elements that including carbonnanotubes of the touch panel and the liquid crystal display screen, themajority of the carbon nanotubes are metallic carbon nanotubes.

It is to be understood that the above-described embodiments are intendedto illustrate rather than limit the invention. Variations may be made tothe embodiments without departing from the spirit of the invention asclaimed. It is envisioned that any element from any embodiment can beused in conjunction with any other embodiment. The above-describedembodiments illustrate the scope of the invention but do not restrictthe scope of the invention.

It is also to be understood that above description and the claims drawnto a method may include some indication in reference to certain steps.However, the indication used is only to be viewed for identificationpurposes and not as a suggestion as to an order for the steps.

What is claimed is:
 1. A liquid crystal display screen, comprising: anupper board comprising a resistance-type touch panel; theresistance-type touch panel comprising: a first electrode platecomprising: a first substrate, a plurality of first transparentelectrodes, the plurality of first transparent electrodes are located onthe first substrate and aligned along a first direction, and a pluralityof first signal wires, each of the first transparent electrodes isconnected to one of the first signal wires; a second electrode plate,spaced from the first electrode plate, comprising: a second substrate, aplurality of second transparent electrodes, the plurality of secondtransparent electrodes are located on the second substrate and alignedalong a second direction, both the second transparent electrodes and thefirst transparent electrodes comprise of a transparent carbon nanotubestructure, the carbon nanotube structure comprises a plurality of carbonnanotubes aligned along a same direction, and a plurality of secondsignal wires, and each of the second transparent electrodes is connectedto one of the second signal wires; wherein the first transparentelectrodes are contacting the second transparent electrodes at aposition where pressing occurs; a lower board comprising a thin filmtransistor panel; and a liquid crystal layer located between the upperboard and the lower board.
 2. The liquid crystal display screen of claim1, wherein the carbon nanotube structure comprises one or more carbonnanotube films.
 3. The liquid crystal display screen of claim 2, whereinthe carbon nanotube structure has a thickness of about 0.5×10⁻³ μm toabout 100 μm.
 4. The liquid crystal display screen of claim 2, whereinthe carbon nanotube films are adjacent to each other or stacked on eachother.
 5. The liquid crystal display screen of claim 2, wherein thecarbon nanotube film comprises a disordered carbon nanotube film.
 6. Theliquid crystal display screen of claim 5, wherein the carbon nanotubesof the disordered carbon nanotube film are entangled with each other. 7.The liquid crystal display screen of claim 2, wherein the carbonnanotube film comprises an ordered carbon nanotube film.
 8. The liquidcrystal display screen of claim 7, wherein the ordered carbon nanotubefilm comprises a plurality of carbon nanotubes joined end to end via vander Waals attractive force.
 9. The liquid crystal display screen ofclaim 1, wherein the carbon nanotube structure comprises at least twocarbon nanotube films stacked on each other, an angle is formed betweenthe carbon nanotubes of two adjacent carbon nanotube films, the angle isin a range about 0 degree to about 90 degrees.
 10. The liquid crystaldisplay screen of claim 1, wherein the carbon nanotubes of the carbonnanotube structure are selected from the group consisting of singlewalled carbon nanotubes, double walled carbon nanotubes, and multiwalled carbon nanotubes, the single walled carbon nanotubes havediameters of about 0.5×10⁻³ μm to about 5×10⁻² μm, the double walledcarbon nanotubes have diameters of about 1.0×10⁻³ μm to about 5×10⁻² μm,the multi walled carbon nanotubes have diameters of about 1.5×10⁻³ μm toabout 5×10⁻² μm.
 11. The liquid crystal display screen of claim 1,wherein the carbon nanotube structure is a composite layer comprising atleast one carbon nanotube film and a polymer material infiltrated in thecarbon nanotube film.
 12. The liquid crystal display screen of claim 11,wherein the polymer comprises of a material that is selected from thegroup consisting of polycarbonate (PC), polymethyl methacrylate acrylic(PMMA), polyethylene terephthalate (PET), benzocyclobutenes (BCB),polystyrene, polyethylene, polycarbonate, and polycycloolefins.
 13. Theliquid crystal display screen of claim 1, wherein the first transparentelectrodes are aligned along a first direction, the second transparentelectrodes are aligned along a second direction, and the first directionis perpendicular to the second direction.
 14. The liquid crystal displayscreen of claim 1, wherein the plurality of the first transparentelectrodes and the plurality of the second transparent electrodes areuniformly arranged, the first and second transparent electrodes havestrip-shaped structures and have width of about 20 μm to about 250 μm,the first and second transparent electrodes have thickness of about0.5×10⁻³ μm to about 100 μm, the first and second transparent electrodeshave a distance therebetween of about 20 μm to about 50 μm.
 15. Theliquid crystal display screen of claim 1, wherein the plurality of thefirst transparent electrodes each has a first end and a second end, thefirst end is electrically connected to the X-coordinates driving sourcevia the first signal wire, the second end is electrically connected to asensor via the first signal wire; the plurality of the secondtransparent electrodes each has a first end and a second end, the firstend of the second transparent electrodes is electrically connected tothe Y-coordinates driving source via the second signal wire, the secondend of the second transparent electrodes is grounded.
 16. The liquidcrystal display screen of claim 1, wherein the plurality of the firstsignal wires are parallel to each other, the plurality of the secondsignal wires are parallel to each other, the first and second signalwires comprise of a material selected from a group consisting of indiumtin oxide, antimony tin oxide, conductive resin, carbon nanotubes, andcombinations thereof.
 17. The liquid crystal display screen of claim 1,wherein the upper board further comprises a first polarizing layer and afirst alignment layer, the first polarizing layer is disposed directlyon a lower surface of the second substrate of the touch panel, the firstalignment layer is disposed on a lower surface of the first polarizinglayer.
 18. The liquid crystal display screen of claim 17, wherein thefirst polarizing layer comprises a plurality of carbon nanotubesarranged along a preferred orientation.
 19. The liquid crystal displayscreen of claim 17, wherein the first polarizing layer has a thicknessof about 1 μm to about 0.5×10³ μm.
 20. The liquid crystal display screenof claim 1, wherein the thin film transistor panel further comprises: athird substrate; a display driving circuit; a plurality of thin filmtransistors disposed the third substrate and electrically connected tothe display driving circuit; and a plurality of pixel electrodes, one ofpixel electrodes being electrically connected to each of the thin filmtransistors.
 21. The liquid crystal display screen of claim 1, whereinthe lower board further comprises a second alignment layer and a secondpolarizing layer, the second polarizing layer is disposed on a lowersurface of the thin film transistor panel, the second alignment layer isdisposed on an upper surface of the thin film transistor panel andadjacent to the liquid crystal layer.
 22. The liquid crystal displayscreen of claim 1, wherein the lower board further comprises a carbonnanotube layer configured for both polarizing light and aligning liquidcrystals, wherein the carbon nanotube layer comprises a plurality ofcarbon nanotubes substantially arranged along a primary direction.
 23. Aliquid crystal display screen, comprising: an upper board comprising aresistance-type touch panel, the resistance-type touch panel comprising:a resistance-type touch panel comprising: a first electrode platecomprising: a first substrate, a plurality of first transparentelectrodes, the plurality of first transparent electrodes are located onthe first substrate, spaced from each other and aligned along a firstdirection, a distance between adjacent first transparent electrodes isin a range from about 20 microns to about 50 microns, and a plurality offirst signal wires, each of the first transparent electrodes isconnected to one of the first signal wires; a second electrode plate,spaced from the first electrode plate, comprising: a second substrate, aplurality of second transparent electrodes, the plurality of secondtransparent electrodes located on the second substrate, spaced from eachother and aligned along a second direction, a distance between adjacentsecond transparent electrodes is in a range from about 20 microns toabout 50 microns, the second transparent electrodes and the firsttransparent electrodes comprise a transparent carbon nanotube structure,the carbon nanotube structure comprises a plurality of metallic carbonnanotubes aligned along a same direction, and a plurality of secondsignal wires, and each of the second transparent electrodes is connectedto one of the second signal wires; wherein the first transparentelectrodes are contacting the second transparent electrodes at aposition where pressing occurs; a lower board comprising a thin filmtransistor panel; and a liquid crystal layer located between the upperboard and the lower board.
 24. A liquid crystal display screen,comprising: an upper board comprising a resistance-type touch panel, theresistance-type touch panel comprising: a first electrode platecomprising: a first substrate, a plurality of first transparentelectrodes, the plurality of first transparent electrodes are located onthe first substrate, spaced from each other and aligned along a firstdirection, and a plurality of first signal wires, each of the firsttransparent electrodes is connected to one of the first signal wires; asecond electrode plate, spaced from the first electrode plate,comprising: a second substrate, a plurality of second transparentelectrodes, the plurality of second transparent electrodes are locatedon the second substrate, spaced from each other and aligned along asecond direction, both the second transparent electrodes and the firsttransparent electrodes comprise a transparent carbon nanotube structure,the carbon nanotube structure comprises at least one ordered carbonnanotube film comprising a plurality of carbon nanotube oriented along asubstantially same direction, and a plurality of second signal wires,and each of the second transparent electrodes is connected to one of thesecond signal wires; wherein the first transparent electrodes arecontacting the second transparent electrodes at a position wherepressing occurs; a lower board comprising a thin film transistor panel;and a liquid crystal layer located between the upper board and the lowerboard.
 25. The resistance-type touch panel as claimed in claim 24, theplurality of carbon nanotubes are joined end to end by van der Waalsattractive force.